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INTRODUCTION The study investigated the effect of untreated cardiac arrest (CA), that is, "no-flow" time, on postresuscitation myocardial and neurological injury, and survival in a pig model to identify an optimal duration that adequately reflects the most frequent clinical scenario. METHODS An established model of myocardial infarction followed by CA and cardiopulmonary resuscitation was used. Twenty-two pigs were subjected to three no-flow durations: short (8-10 min), intermediate (12-13 min), and long (14-15 min). Left ventricular ejection fraction (LVEF) was assessed together with thermodilution cardiac output (CO) and high sensitivity cardiac troponin T (hs-cTnT). Neurological impairment was evaluated by neurological scores, serum neuron specific enolase (NSE), and histopathology. RESULTS More than 60% of animals survived when the duration of CA was ≤13 min, compared to only 20% for a duration ≥14 min. Neuronal degeneration and neurological scores showed a trend toward a worse recovery for longer no-flow durations. No animals achieved a good neurological recovery for a no-flow ≥14 min, in comparison to a 56% for a duration ≤13 min (P = 0.043). Serum NSE levels significantly correlated with the no-flow duration (r = 0.892). Longer durations of CA were characterized by lower LVEF and CO compared to shorter durations (P

Graphical abstract, The identification of new treatments for primary pulmonary arterial hypertension (PAH) is a critical unmet need since there is no a definitive cure for this disease yet. Due to the complexity of PAH, a wide set of methods are necessary to assess the response to a pharmacological intervention. Thus, a rigorous protocol is crucial when experimental studies are designed. In the present experimental protocol, a stepwise approach was followed in a monocrotaline-induced PAH model in the rat, moving from the dose finding study of treatment compounds to the recognition of the onset of disease manifestation, in order to identify when to start a curative treatment. A complete multidimensional evaluation of treatment effects represented the last step. The primary study endpoint was the change in right ventricular systolic pressure after 14 days of treatment; echocardiographic and biohumoral markers together with heart and pulmonary arterial morphometric parameters were considered as secondary efficacy and/or safety endpoints and for the evaluation of the biologic coherence in the different results.

Diabetic nephropathy is associated with cardiovascular morbidity. Angiotensin-converting enzyme (ACE) inhibitors provide imperfect renoprotection in advanced type 2 diabetes, and cardiovascular risk remains elevated. Endothelin (ET)-1 has a role in renal and cardiac dysfunction in diabetes. Here, we assessed whether combination therapy with an ACE inhibitor and ETAreceptor antagonist provided reno- and cardioprotection in rats with overt type 2 diabetes. Four groups of Zucker diabetic fatty (ZDF) rats were treated orally from 4 (when proteinuric) to 8 mo with vehicle, ramipril (1 mg/kg), sitaxsentan (60 mg/kg), and ramipril plus sitaxsentan. Lean rats served as controls. Combined therapy ameliorated proteinuria and glomerulosclerosis mostly as a result of the action of ramipril. Simultaneous blockade of ANG II and ET-1 pathways normalized renal monocyte chemoattractant protein-1 and interstitial inflammation. Cardiomyocyte loss, volume enlargement, and capillary rarefaction were prominent abnormalities of ZDF myocardium. Myocyte volume was reduced by ramipril and sitaxsentan, which also ameliorated heart capillary density. Drug combination restored myocardial structure and reestablished an adequate capillary network in the presence of increased cardiac expression of VEGF/VEGFR-1, and significant reduction of oxidative stress. In conclusion, in type 2 diabetes concomitant blockade of ANG II synthesis and ET-1 biological activity through an ETAreceptor antagonist led to substantial albeit not complete renoprotection, almost due to the ACE inhibitor. The drug combination also showed cardioprotective properties, which however, were mainly dependent on the contribution of the ETAreceptor antagonist through the action of VEGF.

Diabetes aggravates the clinical severity and represents an additional independent risk factor of hypertension. Since both diseases separately concur to cardiomyocyte apoptosis, a mechanism at least partly involving unbalanced oxidative stress, we investigated whether the combination of diabetes and hypertension potentiated cardiac cell death in experimental models, compared to either disease alone. We also evaluated the short-term effects of different drugs in these models. Streptozotocin-induced diabetic normotensive (WKY) or hypertensive (SHR) rats were treated for one week with a DA 2 /α 2 agonist (CHF-1024), a selective β1 adrenergic blocker (metoprolol), an angiotensin II-receptor blocker (valsartan) or a radical scavenger (tempol). In separate experiments, isolated cardiomyocytes were cultured in high glucose medium (25 mM) containing the same drugs. Although the number of apoptotic cardiomyocytes and the myocardial density of oxygen radicals were higher in non diabetic hypertensive than in normotensive controls, diabetes raised these variables to comparable absolute levels in both strains. All drugs except metoprolol significantly reduced apoptosis and oxidative stress in the diabetic animals of both strains and in the isolated myocytes cultured with high glucose. In conclusion, hypertensive rat is no more susceptible than its normotensive control to acute apoptosis induced by diabetes. Oxidative stress might be considered the common trigger for cardiac myocyte apoptosis in both conditions.

Endothelin is elevated in heart failure and contributes to neurohormonal activation, hemodynamic deterioration, and cardiovascular remodeling. Here, we examined its prognostic value in a large population of patients with chronic heart failure.Big endothelin-1 (Big ET-1) and 4 other neurohormones were measured at study entry in 2359 patients enrolled in the Valsartan Heart Failure Trial (Val-HeFT) and their concentrations related to outcome over a median follow-up of 23 months. Baseline concentration of Big ET-1 (median 0.80 pmol/L) was proportional to severity of disease (New York Heart Association class, left ventricular structure and function). High circulating concentrations of brain natriuretic peptide (BNP), creatinine and bilirubin, advanced New York Heart Association class, elevated body mass index, and the presence of atrial fibrillation were independently associated to higher concentrations of Big ET-1. Big ET-1 (ranking second just behind BNP among neurohormonal factors) was an independent predictor of outcome defined as all-cause mortality (hazard ratio 1.49, 95% CI 1.20-1.84, P = .0003) or the combined endpoint of mortality and morbidity (hazard ratio 1.43, 95% CI 1.20-1.69, P.0001) and provided incremental prognostic value compared with BNP.In a large population of patients with symptomatic heart failure, the circulating concentration of Big ET-1, a precursor of the paracrine and bioactive peptide ET-1, was an independent marker of mortality and morbidity. In this setting, BNP remained the strongest neurohormonal prognostic factor.

Blockade of the renin-angiotensin system (RAS) reduces cardiovascular morbidity and mortality in diabetic patients. Ang II-mediated generation of reactive oxygen species (ROS) has been suggested to be involved in several diabetic complications. We investigated whether the inhibition of Ang II production with an ACE inhibitor (ACEi) reduces oxidative stress and limits structural cardiovascular remodeling in a rat model of streptozotocin (STZ)-induced diabetes. Diabetic rats were treated for 7 weeks with an ACEi (lisinopril, 5 mg/kg/d), an antioxidant (N-acetyl-l-cysteine (NAC), 0.5 g/kg/d) and their combination. At sacrifice, ROS in the myocardium and thoracic aorta, LV myocyte number and size and aorta morphology were determined by quantitative histological methods. Superoxide and hydroxyl radical content, detected by dihydroethidium (DHE) and 8-hydroxydeoxyguanosine (8-OHdG), were 6.7 and 4.5-fold, respectively, higher in diabetic myocardium than in non-diabetic controls (p

Aims Plasma levels of individual neurohormones (NH) have been proposed as reliable indicators for risk stratification of patients with heart failure (HF). Mainly because of small sample size, the predictive value of different NH has never been compared, while taking into account demographic, clinical and echocardiographic markers of risk in HF. Methods and results Plasma brain natriuretic peptide (BNP), norepinephrine (NE), renin activity (PRA), aldosterone (aldo) and endothelin were measured in 4300 patients before randomization in Val-HeFT. Univariate and multivariate Cox proportional hazard analyses were performed to investigate the relationship between NH and two primary study outcomes, mortality and combined mortality and morbidity (M/M). Higher baseline values for all NH were related to mortality and M/M, with univariate hazard ratios ranging from 1.13 \[95% CI 0.99–1.30\] (aldo) to 2.47 \[2.13–2.87\] (BNP) for mortality, and from 1.24 \[1.11–1.39\] (aldo) to 2.56 \[2.28–2.89\] (BNP) for M/M. In multivariate analyses, BNP had the strongest association with outcome, followed by NE and PRA. Patients with more activation of renin-angiotensin-aldosterone system tended to show greater benefit from valsartan; but the trend was not statistically significant. Conclusion All the NHs evaluated in 4300 patients with stable moderate to severe HF were found to be significant markers of outcome, despite therapy with ACEi, BB and randomization to an angiotensin receptor blocker or placebo. Several of these markers have been implicated as contributors to progression of HF, but BNP, which is thought to be protective, was the most powerful indicator for poor outcome.

We compared the effects of an ACE inhibitor, captopril, with those of a DA2-dopaminergic/α2-adrenergic receptor agonist (CHF-1024) on neuroendocrine activation and cardiac fibrosis in a model of pressure-overload hypertrophy. Interrenal aortic stenosis was performed in 89 rats, treated with CHF-1024 (0.33, 2 or 6 mg kg−1 day−1), or captopril (1 g/L). Hemodynamic variables were recorded. Cardiac and renal weights, plasma aldosterone, renin activity and urinary catecholamine excretion were measured, as well as cardiac collagen. Blood pressure was lower in stenotic animals treated with CHF-1024 compared to vehicle (161 ± 10 vs 219 ± 10 mmHg, p < 0.01), but LV weight was similar. CHF-1024 elicited a marked dose-dependent attenuation of urinary norepinephrine excretion (1.80 ± 0.18 in controls compared to 0.40 ± 0.14 μg/24 h at the highest dose, p < 0.01) and of LV perivascular fibrosis. Captopril provoked a marked hypotension, reduced cardiac and body weights, plasma aldosterone concentration, dopamine excretion and perivascular collagen. The DA2/α2 agonist CHF-1024 effectively blunts adrenergic drive and cardiac fibrosis in a rat model of pressure overload.

Several studies on disease and treatment effects on neurohormones have been conducted with small numbers of patients, using one blood sample as representative of their states. The aim of this study was to assess the within-patient variability of plasma concentrations of several hormones and cytokines of recent interest, in patients with moderate heart failure and controlled stable background therapy over 3 weeks. Blood for neurohormone and cytokine assays was sampled in duplicate from 18 patients with moderate heart failure. After an initial visit, the patients were kept on stable therapy until the second blood sampling 21 +/- 3 days later. The plasma concentrations of several neurohormones (endothelin, renin, angiotensin II, aldosterone, norepinephrine) and cytokines (interleukin-6 (IL-6), interleukin-13 (IL-13), ciliary neurotrophic factor (CNTF), leukemia inhibitory factor (LIF) and soluble receptor type I of tumour necrosis factor-alpha, (sTNF-RI) were measured with immunochemical methods. Some cytokines (IL-13, CNTF and LIF) were not detected. Despite clinically satisfactory ACE inhibition, circulating angiotensin II and aldosterone levels were still elevated in some patients, suggesting aldosterone escape. The between-visit agreement of plasma concentrations measured in duplicate was less than 35% for all circulating factors, except renin which showed a higher variability throughout the 3-week study period.

Background: Co-administration of ibuprofen (IBU) and isosorbide dinitrate (ISDN) provides synergistic beneficial effects on dystrophic skeletal muscle. Whether this treatment has also cardioprotective effects in this disease was still unknown. Aims: To evaluate the effects of co-administration of IBU and ISDN (a) on left ventricular (LV) structure and function, and (b) on cardiac inflammatory response and fibrosis in mdx mice. Methods: Three groups of mice were studied: mdx mice treated with IBU (50 mg kg−1) + ISDN (30 mg kg−1) administered daily in the diet, mdx mice that received standard diet without drugs and wild type aged-matched mice. Animals were analysed after 10–11 months of treatment. Structural and functional parameters were evaluated by echocardiography while histological analyses were performed to evaluate inflammatory response, collagen deposition, cardiomyocyte number and area. Results: Treatment for 10–11 months with IBU + ISDN preserved LV wall thickness and LV mass. Drug treatment also preserved the total number of cardiomyocytes in the LV and attenuated the increase in cardiomyocyte size, when compared to untreated mdx mice. Moreover, a trend towards a decreased number of inflammatory cells, a reduced LV myocardial interstitial fibrosis and an enhanced global LV function response to stress was observed in treated mdx mice. Conclusions: Treatment for 10–11 months with IBU + ISDN is effective in preventing the alterations in LV morphology of mdx mice while not reaching statistical significance on LV function and cardiac inflammation.

2,3,7,8-Tetrachlorodibenzo-para-dioxin (TCDD) causes abnormalities during heart development. Cardiomyocytes derived from embryonic stem (ES) cells are a robust model for the study of early cardiomyogenesis. Here, we evaluated the effects of TCDD at key stages during the differentiation of mouse ES cells into cardiomyocytes analysing: (i) the transcription of lineage differentiation (Brachyury, Nkx-2.5, Actc-1), cardiac-specific (Alpk3, cTnT, cTnI, cTnC) and detoxification phase I (Cyp1A1, Cyp1A2 and Cyp1B1) and phase II (Nqo1, Gsta1 and Ugt1a6) genes; (ii) the global gene expression; (iii) the ultrastructure of ES-derived cardiomyocytes; (iv) level of ATP production and (v) the immunolocalisation of sarcomeric α-actinin, β-myosin heavy chain and cTnT proteins. We show that TCDD affects the differentiation of ES cells into cardiomyocytes at several levels: (1) induces the expression of phase I genes; (2) down-regulates a group of heart-specific genes, some involved in the oxidative phosphorylation pathway; (3) reduces the efficiency of differentiation; (4) alters the arrangement of mitochondria, that show twisted and disrupted cristae, and of some sarcomeres, with misalignement or disarrangement of the myofibrillar organisation and (5) reduces ATP production. This study provides novel evidences that TCDD impairs cardiomyocyte differentiation. Sarcomeres and mitochondria could be a target for dioxin toxicity, their disruption representing a possible mechanism developing cardiac injury.

The renin-angiotensin system plays a role in the etiology of hypertension and the pathophysiology of cardiac and renal diseases in humans. Ang II is the central product of this system and is involved in regulating immune responses, inflammation, cell growth, and proliferation by acting through Ang II type 1 receptors (AT1 and AT2). Here, we show that targeted disruption of the Agtr1a gene that encodes AT1A results in marked prolongation of life span in mice. Agtr1a-/- mice developed less cardiac and vascular injury, and multiple organs from these mice displayed less oxidative damage than wild-type mice. The longevity phenotype was associated with an increased number of mitochondria and upregulation of the prosurvival genes nicotinamide phosphoribosyltransferase (Nampt) and sirtuin 3 (Sirt3) in the kidney. In cultured tubular epithelial cells, Ang II downregulated Sirt3 mRNA, and this effect was inhibited by an AT1 antagonist. These results demonstrate that disruption of AT1 promotes longevity in mice, possibly through the attenuation of oxidative stress and overexpression of prosurvival genes, and suggests that the Ang II/AT1 pathway may be targeted to influence life span in mammals.

Background—Despite widespread clinical use as a prognostic marker in ischemic heart disorders, the actual pathogenetic role of the short pentraxin, C-reactive protein, has not undergone stringent genetic testing because of evolutionary divergence between mouse and humans. The long pentraxin PTX3 is conserved in evolution, is expressed in the heart under inflammatory conditions, and is a candidate prognostic marker in acute myocardial infarction. It was therefore important to assess whether PTX3 plays a pathogenetic role in acute myocardial infarction.Methods and Results—In a model of acute myocardial infarction caused by coronary artery ligation and reperfusion, tissue mRNA expression and circulating levels of PTX3 increased. The interleukin-1R–MyD88 pathway plays a pivotal role in the induction of PTX3 transcript after ischemia.ptx3-deficient mice showed exacerbated heart damage (33% larger infarcts in null mice;P=0.0047). Increased myocardial damage inptx3-deficient mice was associated with a greater no-reflow area, increased neutrophil infiltration, decreased number of capillaries, and increased number of apoptotic cardiomyocytes. In addition,ptx3-deficient mice with acute myocardial infarction showed higher circulating levels of interleukin-6 and increased C3 deposition in lesional tissue. The phenotype was reversed by exogenous PTX3.Conclusions—Thus, PTX3 plays a nonredundant, regulatory, cardioprotective role in acute myocardial infarction in mice. Our results suggest that modulation of the complement cascade contributes to the cardioprotective function of PTX3.

In addition to its role as the main regulator of erythropoiesis, erythropoietin has a wide range of protective, antiapoptotic activities in vitro and in vivo, particularly in the brain and, as more recently shown, in the heart.1 Of note, erythropoietin is not exclusively produced by fetal liver and adult kidney but is expressed also in the brain, where it can be induced by hypoxia or ischaemia. Several studies underline the potential role of erythropoietin in mediating hypoxic–ischaemic preconditioning in the brain.1 On the other hand, the heart has never been described as a site for erythropoietin production. However, hypoxia inducible factor 1 (HIF-1), the main transcriptional regulator of erythropoietin, is induced by hypoxia in myocardial cells in vivo and in vitro.1 HIF-1 has recently been reported to mediate hypoxic preconditioning in the heart.2 We investigated whether, as in the brain, erythropoietin is produced in mouse ischaemic heart.3 After permanent coronary artery occlusion (CAO), CD1 mice were killed.4 For immunohistochemistry, the portion of heart below the ligature was formalin fixed, paraffin embedded, cut into 5 µm thick sections, and processed as previously described (antierythropoietin: H-162, 1:100; Santa Cruz Biotechnology, Santa Cruz, …

Excessive deposition of extracellular matrix proteins during aging leads to a progressive reduction of myocardial and arterial compliances. The increased cardiovascular stiffness may in turn determine a reduced capacity of the aged heart to respond to stressful situations. Our knowledge on the biology of extracellular matrix during aging derives mainly from observations made in animal models. The age-dependent accumulation of collagen in the heart is not related to an increased synthesis, but rather to a reduction of its degradation by specific matrix metalloproteinases and to an increased cross-linking of mature collagen that renders it more resistant to degradation. Specific pharmacological treatments are currently in use to limit or even reverse the progressive stiffening of the arteries and myocardium.

Background: The incidence of cardiovascular diseases increases rapidly with age, and the elderly suffer higher morbidity and mortality. Aldosterone blockers have shown. benefits in patients with left ventricular (LV) dysfunction and heart failure after myocardial infarction (MI). However, aldosterone blockade efficacy has not been explored in aged animals with MI. Methods and Results: Small-to-moderate MI was induced by coronary artery ligation in 16-month old rats, divided into 3 groups: sham-operated (control, n = 9), MI (n. = 9), and MI fed a diet containing eplerenone (120 mg/kg/day, MI+Eplerenone, n = 9). given 18 days postsurgery and up to sacrifice 3 months later. At. sacrifice, untreated MI rats did not show overt systolic dysfunctiom but they had (1) echocardiographic evidences of impaired relaxation (increase of E wave deceleration time and of isovolumic relaxation time, decrease of peak E wave velocity), (2) hemodynamically impaired LV relaxation (LV -dP/dt from 7413 +/- 720 to 4956 +/- 475 mm Hg/s, P < .05), and (3) significant increase of collagen content in LV interstitium (from 4.27 +/- 0.23 to 5.34 +/- 0.24%, P < .01), and in aorta. (from 19 +/- 1 to 24 +/- 2%, P < .05). Eplerenone normalized echocardiographic and hemodynamic evidences of diastolic dysfunction, as well as myocardial. interstitial collagen and aortic fibrosis. (all parameters statistically different from untreated MI). Conclusion: In aged rats with small to moderate MI, eplerenone normalized diastolic relaxation, possibly through a reduction of interstitial fibrosis.

Diabetes and oxidative stress concur to cardiac myocyte death in various experimental settings. We assessed whether N-acetyl-L-cysteine (NAC), an antioxidant and glutathione precursor, has a protective role in a rat model of streptozotocin (STZ)-induced diabetes and in isolated myocytes exposed to high glucose (HG). Diabetic rats were treated with NAC (0.5 g/kg per day) or vehicle for 3 months. At sacrifice left ventricle (LV) myocyte number and size, collagen deposition and reactive oxygen species (ROS) were measured by quantitative histological methods. Diabetes reduced LV myocyte number by 29% and increased myocyte volume by 20% compared to non-diabetic controls. NAC protected from myocyte loss (+25% vs. untreated diabetics, P < 0.05) and reduced reactive hypertrophy (‐16% vs. untreated diabetics, P < 0.05). Perivascular fibrosis was high in diabetic rats (+88% vs. control, P < 0.001) but prevented by NAC. ROS production and fraction of ROS-positive cardiomyocyte nuclei were drastically raised in diabetic rats (2.4- and 5.1-fold vs. control, P < 0.001) and normalized by NAC. In separate experiments, isolated adult rat ventricular myocytes were incubated in a medium containing high concentrations of glucose (HG, 25 mM) ± 0.01 mM NAC; myocyte survival (Trypan blue exclusion and apoptosis by TUNEL) and glutathione content were evaluated. The number of dead and apoptotic myocytes increased five and 6.7-fold in HG and glutathione decreased by 48% (P < 0.05). NAC normalized cell death and apoptosis and prevented glutathione loss. NAC effectively protects from hyperglycemia-induced myocyte cell death and compensatory hypertrophy through direct scavenging of ROS and replenishment of the intracellular glutathione content. © 2004 Elsevier Ltd. All rights reserved.

Cardiac myocytes have been traditionally regarded as terminally differentiated cells that adapt to increased work and compensate for disease exclusively through hypertrophy. However, in the past few years, compelling evidence has accumulated suggesting that the heart has regenerative potential. Recent studies have even surmised the existence of resident cardiac stem cells, endothelial cells generating cardiomyocytes by cell contact or extracardiac progenitors for cardiomyocytes, but these findings are still controversial. We describe the isolation of undifferentiated cells that grow as self-adherent clusters (that we have termed “cardiospheres”) from subcultures of postnatal atrial or ventricular human biopsy specimens and from murine hearts. These cells are clonogenic, express stem and endothelial progenitor cell antigens/markers, and appear to have the properties of adult cardiac stem cells. They are capable of long-term self-renewal and can differentiate in vitro and after ectopic (dorsal subcutaneous connective tissue) or orthotopic (myocardial infarction) transplantation in SCID beige mouse to yield the major specialized cell types of the heart: myocytes (ie, cells demonstrating contractile activity and/or showing cardiomyocyte markers) and vascular cells (ie, cells with endothelial or smooth muscle markers).

Background— Brain natriuretic peptide (BNP) and norepinephrine (NE) are strongly related to severity of and are independent predictors of outcome in heart failure. The long-term effects of angiotensin receptor blockers on BNP and NE in heart failure patients are not known. Methods and Results— Both BNP and NE were measured in 4284 patients randomized to valsartan or placebo in the Valsartan Heart Failure Trial (Val-HeFT) at baseline and 4, 12, and 24 months after randomization. The effects of valsartan were tested by ANCOVA, controlling for baseline values and concomitant ACE inhibitors and/or β-blockers. BNP and NE concentrations were similar at baseline in the 2 groups and were decreased by valsartan starting at 4 months and up to 24 months. BNP increased over time in the placebo group. At the end point, least-squares mean (±SEM) BNP increased from baseline by 23±5 pg/mL in the placebo group (n=1979) but decreased by 21±5 pg/mL (n=1940) in the valsartan group ( P P =0.0003). Concomitant therapy with both ACE inhibitors and β-blockers significantly reduced the effect of valsartan on BNP but not on NE ( P for interaction=0.0223 and 0.2289, respectively). Conclusions— In Val-HeFT, the largest neurohormone study in patients with symptomatic chronic heart failure, BNP and NE rose over time in the placebo group. Valsartan caused sustained reduction in BNP and attenuated the increase in NE over the course of the study. These neurohormone effects of valsartan are consistent with the clinical benefits reported in Val-HeFT.